Not all the crusades are entirely civic-minded. In more than a few cases, virtual mobs have harassed offending officials, posting personal information and other details. The nickname for such mobs, “human-flesh search engines,” hints at their pitiless nature.

But the Internet campaigns have repeatedly produced results. Six officials were punished or fired in the prison beating. The Nanjing official with the flashy watch was sacked. The Yunnan dog killings have provoked harsh criticism, even in state-run newspapers.

Most such cases, says Mr. Xiao, the Berkeley professor, spawn tens or hundreds of thousands of mentions on Internet blogs and other forums.

As the embattled government of President Mahmoud Ahmadinejad appears to be trying to limit Internet access and communications in Iran, new kinds of social media are challenging those traditional levers of state media control and allowing Iranians to find novel ways around the restrictions.

One of the most important reasons that the Islamists were able to covertly organize and mobilize, and be prepared when the lids in their societies were loosened a bit, was because they had the mosque — a place to gather, educate and inspire their followers — outside the total control of the state.

[...] What is fascinating to me is the degree to which in Iran today — and in Lebanon — the more secular forces of moderation have used technologies like Facebook, Flickr, Twitter, blogging and text-messaging as their virtual mosque, as the place they can now gather, mobilize, plan, inform and energize their supporters, outside the grip of the state.